108 Impacts of dam age and milk production on cow/calf profitability

摘要

Cow herd profitability can be greatly influenced by reproductive success, average age of herd, and genetic potential within the environment. Productivity is influenced by cow age with calf weaning weight, increasing from 2 to 5 yr of age in dams. With that in mind, increasing average age of the cowherd has the potential to increase cow/calf profitability. Culling cows before 5 yr of age negatively impacts production efficiency due to decreased calf weaning weight in younger cows and subsequently, increase replacement rate and costs. Therefore, reproduction in young cattle is important to overall economic efficiency within the cow herd and a driving factor in longevity. Due to decreased reproduction and offspring performance, young females have previously been considered an economic liability. The effect of increased average cow age within the herd along with increased pregnancy rate of young cows has shown to increase production efficiency by decreasing replacement rates and adding greater production potential with increased calf weaning weights. In young beef cows, partitioning nutrients away from lactational demands allows for nutrients to be utilized for cow growth and reproduction. An increase in selection for milk production has resulted in beef cows undergoing greater nutritional stress during early lactation, which ultimately reduces cowherd reproduction and efficiency. Although a big emphasis is placed on output traits, economic value of reproduction is 5 times greater than growth or maternal output traits in beef cattle. In addition, the value of the added milk production may not fully be captured, due to extensive environments with limited nutrients. Even in environments with greater feed resources, selection for milk production may led to a decrease in reproduction, production efficiency, and cowherd retention rate.